The following was done using the cases I mentioned. I started with 5 cases each of .223 Remington and .308 Winchester. The case data is as follows and these were new factory cases.
Case: .308 Winchester RP Manufacture New.
Primer Pocket Diameter: 0.208".
Case Measured Head to Datum: 1.628" after sizing. About -0.002" of Nominal.
Case Length: Trimmed to 2.005"
Case: .223 Remington Win Manufacture New
Primer Pocket Diameter: 0.173"
Case Measured Head to Datum: 1.461" after sizing. About -0.003" of Nominal.
Case Length: Trimmed to 1.750"
The cases before being manually primed:
Primers and Primed cases. I used CCI Magnum primers on both calibers. The seated primers were seated till they bottomed out placing them right around 0.003" below the case heads. The CCI-250 Large Rifle had a diameter of 0.210" and the CCI-200 Small Rifle measured a 0.174" diameter.
The rifles used were both Remington 700 bolt gun variations. The chamber head space on these rifles are right around 1.632" for the .308 gun and 1.4655 for the .223 gun. Headspace as measured using Forrester chamber gauges of known accuracy.
Here is what the spent primers looked like after firing in an unobstructed barrel. They did try to back out a little finishing as flush with the case heads. If we look closely at the single primer images there is some shiny bright metal. This is where the primers backed into the bolt face stopping flush with the case heads. Look around 2 O'Clock on the .308 case.
Following firing of the primers the case sizes did not change. The cases as measured from case head to shoulder datum were the same for all five of each caliber. The .308 Winchester went in as 1.628" and came out as 1.628" and the .223 Remington cases went in at 1.461" and came out as 1.461" so nothing case dimensional wise changed. With the chamber heads paces I posted and the case dimensions posted while there was room for change there was no change. Additionally the case lengths remained the same also.
I did remove the bolts from both rifles prior to firing the primers and both extractors firmly grasped the case heads so when chambered in the rifles the case heads should have been flush on the bolt faces. Primer protrusion on both rifles is right around 0.060" and as can be seen both rifles made good deep primer strikes.
While absolutely none of this has anything to do with primer sealants it did make for an entertaining part of my afternoon.
Ron